Search found 8 matches
- Fri Jul 05, 2013 10:52 am
- Forum: Fender Discussion
- Topic: Bandmaster
- Replies: 11
- Views: 2238
Re: Bandmaster
Gotta be an early silverface-that's still a pretty neat wiring job. I think the stamp in the chassis saying 11th week of 1968. First production year of the silverface bandmasters. Inside all blackface items, no spaghetti and the famous AA768 circuit. Mint condition. A keeper! Yes, recommend OT from...
- Wed Aug 08, 2012 11:27 am
- Forum: Dumble Discussion
- Topic: For anyone wanting to set the PI Trim pot
- Replies: 63
- Views: 84911
Re: For anyone wanting to set the PI Trim pot
I really enjoyed your postings. I just wanna emphasize the importance of matched tubes (PI). If not both triodes have the exact amplification curves, the whole adjustment makes no sense. And each called adjust method is getting you closer to the perfect balance. But there is no perfect balance. At l...
- Wed Aug 10, 2011 8:37 am
- Forum: Technical Discussion
- Topic: ( ONE MORE!!!!! ) OT question
- Replies: 19
- Views: 4200
Re: ( ONE MORE!!!!! ) OT question
@gary The primary of the OT is fix. It's just depending on the type of tube (or how much tubes you use in the power stage). It's in the data sheet called load resistance necessary between Anode and Anode. The impedance is a more complex thing. It's the resistance depending on the frequence (includin...
- Wed Aug 03, 2011 1:17 pm
- Forum: Technical Discussion
- Topic: ( ONE MORE!!!!! ) OT question
- Replies: 19
- Views: 4200
Re: ( ONE MORE!!!!! ) OT question
Phil is right. The word is load resistance . In the data sheet of the 6L6 exists a value: load resistance (AB1, fixed bias, tetrode ...) that the tubes expecting when they (sorry) look at the ot. Remember all power tubes are parallel. If the ot was build for 4 6L6 parallel for a 4Ohms speaker, 2 6L6...
- Wed Aug 03, 2011 12:16 pm
- Forum: Technical Discussion
- Topic: Question about matching tubes - pairs versus quads
- Replies: 8
- Views: 1711
Re: Question about matching tubes - pairs versus quads
Hi everyone!
The bias is one point the matching of tubes is another. With bias adjustment you're looking for the correct working point. Matching means comparing the whole amplifying curves and choosing tubes with similar values (how much is the amplifying factor at Imput 1 Volt, 2 Volts ...)
Tom
The bias is one point the matching of tubes is another. With bias adjustment you're looking for the correct working point. Matching means comparing the whole amplifying curves and choosing tubes with similar values (how much is the amplifying factor at Imput 1 Volt, 2 Volts ...)
Tom
- Wed Aug 03, 2011 11:26 am
- Forum: Dumble Discussion
- Topic: #124 NFB Resistor
- Replies: 17
- Views: 3826
Re: #124 NFB Resistor
My understanding is that for resistors to exhibit this behavior there must be around 100V across them. The NFB resistor does not get near that. See: http://www.geofex.com/article_folders/carbon_comp/carboncomp.htm The geofex article is talking about a sinus wave 100V AC over a 50V DC resulting in a...
- Tue Aug 02, 2011 8:11 am
- Forum: Dumble Discussion
- Topic: #124 NFB Resistor
- Replies: 17
- Views: 3826
Re: #124 NFB Resistor
Don't want sombody confusing. Sorry, english is not my home language. 1 Watt is enough and stable at this position. Mr. Dumble often choose the bigger 2 Watts because they sound warmer. Resistors: Carbon Compress resistors sound different than carbon film and metal oxide. From warmer to more compact...
- Mon Aug 01, 2011 2:41 pm
- Forum: Dumble Discussion
- Topic: #124 NFB Resistor
- Replies: 17
- Views: 3826
Re: #124 NFB Resistor
Hi Steve! 1 Watt is enough in a electrically manner. But Mr. Dumble is aware of choosing his materials as a sound designer. The 2 watts Carbon Comps are famous for their overtones on big voltage jump positions(and their noise and heat drift too). Nowadays 2 Watts CC are rare and expensive. However t...